Re: [PATCH v2 0/3] iio: adc: ad7124: Fix 3dB filter frequency reading

[Jonathan Cameron <jic23@kernel.org>]

On Mon, 17 Mar 2025 12:52:46 +0100
Uwe Kleine-König <u.kleine-koenig@baylibre.com> wrote:

> Hello,
> 
> (implicit) v1 of this patch set is available at
> https://lore.kernel.org/linux-iio/cover.1741801853.git.u.kleine-koenig@baylibre.com
> .
> 
> Changes since then:
> 
>  - Reorder patches to have the cleanup ("Make register naming
>    consistent") last
>  - Drop write support for the filter_low_pass_3db_frequency property
>    which is completely broken.
>  - trivially rebase to todays iio/togreg
> 
> I wonder if there is a way to remove the writable permission of the
> filter_low_pass_3db_frequency sysfs file instead of erroring out when a
> value is written. Hints welcome.

Unfortunately not. With a lot of hindsight that is a flaw in the way
we generate sysfs attributes. IIRC when hwmon added similar they
avoided that trap.  To retrofit it onto IIO now we'd have to have
some form of complex permissions query or duplicate all the masks
to allow r and w separately.

Jonathan


> 
> Best regards
> Uwe
> 
> Uwe Kleine-König (3):
>   iio: adc: ad7124: Fix 3dB filter frequency reading
>   iio: adc: ad7124: Remove ability to write
>     filter_low_pass_3db_frequency
>   iio: adc: ad7124: Make register naming consistent
> 
>  drivers/iio/adc/ad7124.c | 208 ++++++++++++++++-----------------------
>  1 file changed, 84 insertions(+), 124 deletions(-)
> 
> 
> base-commit: 8dbeb413806f9f810d97d25284f585b201aa3bdc